Full-scale fatigue tests on a novel box-shaped steel rod of a spatial arch bridge for fatigue assessment

Abstract

A novel leaning-type spatial arch bridge without thrust was designed as a landmark in a major urban city. In order to alleviate the higher negative reaction force at side span and enhance the lateral stability, commonly the case within this type bridge, a large-size replaceable box-shaped steel rod with pinned connections was introduced. The fatigue behaviour of the box-shaped steel rod and related upper and lower anchorage segments was investigated through a full-scale constant-amplitude fatigue test under axial loading. In comparison to the fatigue test results, the fatigue evaluation based on Eurocode 3 nominal stress design curve FAT56 considerably overestimated the fatigue strength of critical welded detail in box-shaped steel rod, which was underrated according to the universal International Institute of Welding effective notch stress design curve FAT225. The presented full-scale programme also validated the applicability of the latter method, which presented conservative results, to large-size thick-plate (80 mm) welded joints. The conclusion based on the test and theoretical results may provide a reference for the fatigue design of adopting box-shaped steel rod in spatial arch bridges.

Innovative Design of Novel Main and Secondary Arch Collaborative Y-Shaped Arch Bridge and Research on Shear Lag Effect of Its Unconventional Thin-Walled Steel Box Arch Ribs

“…The concept of using high-performance steel for arch ribs and main girders to increase the span of special-shaped arch bridges has greatly encouraged the engineering practice of building large-span special-shaped arch However, in design practice, the biggest challenge encountered while increasing the span of special-shaped steel box arch bridges is the lack of stiffness and the prominent thin-wall effect caused by the thinning of steel box sections. Meanwhile, the development of special-shaped steel box arch bridges is increasingly characterized by diversified structural forms, manifold landscape shapes and complex bearing states, which makes the structural force transfer mechanism and force change pattern of special-shaped steel box arch bridges difficult to grasp [12][13][14]. For each particular special-shaped steel box arch bridge, there are still many issues related to design details and mechanical behavior [15].…”